MANKATO, Minn. — Mike Zimmer was at Adrian Peterson’s first regular-season NFL game in 2007, watching from the opposing sideline as Peterson took a short swing pass 60 yards for his first touchdown.

Zimmer was the Atlanta Falcons’ defensive coordinator at the time. He’s able to appreciate such a play a little more these days as Peterson’s coach with the Minnesota Vikings.

"Once he gets the ball in his hands and if it’s in the open field, it’s bad news," Zimmer said Saturday.

Zimmer knows the explosive, big-play potential of Peterson well. So does offensive coordinator Norv Turner, who has talked about getting Peterson in the open field and more involved in the passing game since he was hired by Zimmer.

Plays like Peterson’s first touchdown in 2007 are just what the Vikings have in mind. Peterson’s impact in the passing game has been limited in recent years. Zimmer and Turner are hoping to pull more production from the six-time Pro Bowl back this season by making him more of a receiver.

"We’re doing a lot of things now, and some of the things he does really well and some of the things he doesn’t do as well," Turner said. "That’s a coach’s job, to find out the things he does best and let him do those things. We’re going to try to not ask him to do things he’s not comfortable with. But there’s enough things he does well as a receiver that I feel like he’s going to make big plays in the passing game."

Peterson had 29 catches last season for 171 yards. Of the 13 backs who also ran for 1,000 yards, only two others — Washington’s Alfred Morris and San Francisco’s Frank Gore — had fewer catches. In contrast, Philadelphia’s LeSean McCoy averaged only 10 yards more per game than Peterson last year, but had 52 catches for 539 additional yards.

Peterson’s catches increased each of his first three seasons in the league, leading to a career-high 43 for 436 in 2009. His impact in the passing game varied over the next four seasons, but he did have 40 catches in his MVP-winning 2012 season.

"He runs good routes," Zimmer said. "He catches the ball good. He caught a lot out here today. There’s times when he’ll double catch it a little bit but most of the time he’s pretty darn good. And people are afraid of his speed, which gives him some area to beat people underneath or beat people to the perimeter. I think he’ll be a good weapon."

With more of an emphasis on Peterson catching the ball, perhaps he’ll be used more on third downs, as well. Toby Gerhart had taken much of the third-down responsibilities in recent seasons. But Gerhart signed with the Jacksonville Jaguars in the offseason, creating an opening for Peterson, backup Matt Asiata or possibly rookie Jerick McKinnon to fill.

Turner said Saturday Peterson’s third-down presence is still being determined. Turner believes Peterson has the ability to succeed in the role, even in a blocking role which has been seen as one of Peterson’s weaknesses.

"That’s the two things the backs do, they get into position to make big plays and then they give the quarterback an outlet when he’s getting pressure," Turner said. "I believe that Adrian will certainly be able to do that. He’s an outstanding pass protector when you keep him in his element. We don’t want him blocking defensive ends. We don’t want him blocking 280-pound outside linebackers. When he’s blocking the people he should be blocking, he’s very good in pass protection."

Don’t forget Asiata: Peterson isn’t the only back catching the attention of the coaches. Matt Asiata, who played well in two games while filling in for Peterson and Gerhart at the end of last season, is carving out his own role.

"One of the guys who’s been as impressive to me as anyone offensively is Matt Asiata," Turner said. "He finished the season strong and he is in great shape and he gives you that big pounder, but he’s an excellent athlete. He catches, he’s got good change of direction, he’s a good pass protector. I know Jerick’s got a lot of attention and I’ve said good things about him, but I think our backfield situation is really in good shape."

Asiata had three touchdowns in a win against Philadelphia, while getting 30 carries. In the regular-season finale, he had 14 carries for 115 yards, his first NFL 100-yard game.

"Matt’s doing a great job," Zimmer said. "He’s elusive. He’s got a little bit of a shift and sneakiness about him the way he goes. He catches the ball good. He doesn’t make mistakes. So, he’s been good."

Zimmer was surprised a bit by the 234-pound Asiata’s elusiveness. Asiata is a former fullback.

"Because I really didn’t know him," Zimmer said of his surprise. "I mean, when we got ready to play them last year, I knew who he was but it wasn’t like Adrian. But he’s impressed me."

Injury update: Receiver Cordarrelle Patterson was still held out of practice on Saturday as he deals with a foot injury. He worked with trainers on a side field and is still considered day to day.

"I think he’s improving every day," Zimmer said. "I saw him do some stuff today, so won’t be long I don’t believe. I’ll be surprised if it’s long."

Zimmer said Patterson told him of the foot injury before the team reported to training camp. Patterson was held back from the team’s conditioning test on Thursday.

"I know Cordarrelle is champing at the bit," Turner said. "He wants to get going. So, I hope it will be sooner than later."

Cornerback Captain Munnerlyn, on the physically unable to perform list with a hamstring injury, is also making progress. Zimmer said it could be a "couple more days" for Munnerlyn.

With Munnerlyn out, coaches are getting an extended look at other cornerbacks on the roster.

"One of the things we have to find is a backup nickel," Zimmer said. "We’ve had Jabari Price in there. We’ve had Kendall James in there. We’ve had Shaun Prater in there. So, they’re getting a lot of good reps, which is good because that’s such an important position."

Safety Andrew Sendejo ran on a side field with trainers, too. He is still dealing with back and ankle injuries, which Zimmer said date back to last season.

"Obviously it’s a concern," Zimmer said. "I haven’t seen him one day, so I don’t know really anything."